Percutaneous Mechanical Thrombectomy Using the AcoStream Thrombus Aspiration System for Acute Superior Mesenteric Artery Embolism.

BACKGROUND: This study was performed to summarize our experience in treating acute superior mesenteric artery embolism (SMAE) by percutaneous mechanical thrombectomy (PMT). METHODS: Between January 2023 and October 2023, 18 patients presenting with acute mesenteric ischemia were admitted to our center, including 11 cases of SMAE, 3 cases of superior mesenteric artery thrombosis, and 4 cases of superior mesenteric vein thrombosis. We retrospectively reviewed 8 patients (4 males and 4 females; range, 51-79 years; mean, 62.50 ± 9.67 years) who underwent treatment of acute SMAE using the AcoStream system. The patients had no obvious evidence of intestinal necrosis as shown by peritoneal puncture or computed tomography. Thrombectomy was performed on the superior mesenteric artery (SMA) using an 8F AcoStream thrombus aspiration system (Acotec, China). The demographics, risk factors, therapeutic effect, complications, mortality, and follow-up of the study population were assessed. RESULTS: The technical success rate was 100%. After 1-3 passes (2.38 ± 0.92) and aspiration thrombectomy, complete thrombus removal was achieved in 7 (87.50%) patients. One patient received an adjunctive catheter-directed thrombolysis due to partial thrombus removal. Thrombolysis was conducted for 2 days, resulting in complete resolution of the thrombus. The other 7 patients did not receive adjunctive endovascular intervention due to complete thrombus removal and no residual stenosis. No distal embolization or device-related complications were noted during the procedure. After the procedure, sufficient clinical improvement was seen in 6 patients within 1-2 days. Two patients showed no significant improvement of their symptoms. Laparotomy was performed on day 1 and day 2 after thrombectomy in patients 3 and 7, respectively. Intestinal necrosis was diagnosed operatively and intestinal resection was performed. All patients were discharged 6-15 days (9.50 ± 3.07) after admission without perioperative complication or death. The mean follow-up period was 5.00 ± 3.30 months (range, 1-10 months), and the follow-up rate was 100%. During the follow-up, all patients remained symptom-free. Computed tomography angiography images showed good flow in the trunk and branches of the SMA in all patients. CONCLUSIONS: PMT using the AcoStream system is a minimally invasive, safe, and effective technique for acute SMAE. Early application of PMT can achieve immediate revascularization of the SMA and have the potential advantage of avoiding laparotomy or reducing the extension of enterectomy, as it could theoretically restore intestinal perfusion in less time than open revascularization. If the symptoms do not improve after PMT, exploratory laparotomy should be scheduled as soon as possible. Further studies are necessary on this field to confirm these findings.

Hemodynamics in nutcracker syndrome: implications for diagnosis.

BACKGROUND: Nutcracker syndrome is a disease characterized by complex symptoms, making its diagnosis challenging and often delayed, often resulting in a painful experience for the patients. OBJECTIVE: This study aimed to investigate the pathogenesis of nutcracker syndrome through the perspective of hemodynamics by simulating blood flow with varying compression degrees of the left renal vein. METHODS: 3D patient-specific vascular models of the abdominal aorta, superior mesenteric artery and left renal vein were constructed based on CT images of patients suspected of having nutcracker syndrome. A hemodynamic simulation was then conducted using computational fluid dynamics to identify the correlation between alterations in hemodynamic parameters and varying degrees of compression. RESULTS: The study indicated the presence of an evident gradient in velocity distribution over the left renal vein with relatively high degrees of stenosis (α ≤ 50°), with maximum velocity in the central region of the stenosis. Additionally, when the compression degree of the left renal vein increases, the pressure distribution of the left renal vein presents an increasing number of gradient layers. Furthermore, the wall shear stress shows a correlation with the variation of blood flow velocity, i.e., the increase of wall shear stress correlates with the acceleration of the blood flow velocity. CONCLUSIONS: Using computational fluid dynamics as a non-invasive instrument to obtain the hemodynamic characteristics of nutcracker syndrome is feasible and could provide insights into the pathological mechanisms of the nutcracker syndrome supporting clinicians in diagnosis.

Factors associated with false lumen changes in patients with superior mesenteric artery dissection.

BACKGROUND: False lumen changes (FLCs) are the main reference for the prognosis judgment and treatment plan selection for type IIa superior mesenteric artery dissection (SMAD). METHODS: For this retrospective study, 55 patients with symptomatic type IIa SMAD were included. Computational fluid dynamics (CFD) analysis was used to explore the hemodynamic basis of FLCs. Correlation and multiple linear regression analyses were performed to identify clinical, morphological and hemodynamic factors associated with FLCs. RESULTS: The FLCs of patients with successful conservative treatment (n = 29) are significantly higher than those with failed conservative treatment (n = 26) (58.5 ± 21.1% vs 10.9 ± 17.4%, p < 0.0001). Positive correlations were seen between FLCs and the morphological parameters false lumen length (FLL)/dissection entrance length (DEL) and FLL. In terms of hemodynamic parameters, negative correlations were seen between FLCs and time-averaged wall shear stress (TAWSS), vorticity, and high areas of TAWSS and vorticity, whereas positive correlations were seen between FLCs and oscillatory shear index (OSI), relative residence time (RRT), and high areas of OSI and RRT. Multiple linear regression analysis identified symptom duration (odds ratio [OR], 0.93; 95% CI, 0.91-0.96; p < 0.0001), FLL/DEL (OR, 1.30; 95% CI, 1.01-1.67; p = 0.044), and high RRT area (OR, 2.03; 95% CI, 1.48-2.78; p < 0.0001) as predictors of FLCs. CONCLUSION: The clinical predictor symptom duration, morphological factor FLL/DEL, and the hemodynamic factor high RRT area can serve as predictors of FLCs in patients with symptomatic type IIa SMAD.

Reduced Relaxant Response to Adenine in the Superior Mesenteric Artery of Spontaneously Hypertensive Rats.

We investigated the vascular response to nucleobase adenine using freshly isolated superior mesenteric arteries of spontaneously hypertensive rats (SHR) and its control, Wistar Kyoto (WKY) rats. Endothelium-dependent and endothelium-independent relaxations were assessed in isolated segments in an organ bath. The releases of the metabolites of thromboxane A2 and prostaglandin I2 were also detected. Adenine induced vasorelaxation in both the endothelium-intact and endothelium-denuded arteries in a concentration-dependent manner. In the SHR group, the adenine-induced relaxation was slightly but significantly reduced in the endothelium-intact rings when compared with that in the WKY group. However, the relaxation in the endothelium-denuded rings were similar between the two groups. The difference in the adenine-mediated relaxation in the superior mesenteric arteries between the SHR and WKY groups was eliminated by endothelial denudation and a nitric oxide (NO) synthase inhibitor. In the absence and presence of adenine, SHR tended to have higher levels of metabolites of thromboxane A2 and prostaglandin I2 compared with WKY. However, adenine did not induce the release of these substances in the arteries in both the SHR and WKY groups. These results suggest that the reduced adenine-mediated relaxation in the superior mesenteric arteries in SHR is due to a lack of contribution from the endothelium-derived NO and not from the release of prostanoids.

Effect of ingesting a meal and orthostasis on the regulation of splanchnic and systemic hemodynamics and the responsiveness of cardiovascular α1-adrenoceptors.

Postprandial orthostasis activates mechanisms of cardiovascular homeostasis to maintain normal blood pressure (BP) and adequate blood flow to vital organs. The underlying mechanisms of cardiovascular homeostasis in postprandial orthostasis still require elucidation. Fourteen healthy volunteers were recruited to investigate the effect of an orthostatic challenge (60°-head-up-tilt for 20 min) on splanchnic and systemic hemodynamics before and after ingesting an 800-kcal composite meal. The splanchnic circulation was assessed by ultrasonography of the superior mesenteric and hepatic arteries and portal vein. Systemic hemodynamics were assessed noninvasively by continuous monitoring of BP, heart rate (HR), cardiac output (CO), and the pressor response to an intravenous infusion on increasing doses of phenylephrine, an α1-adrenoceptor agonist. Neurohumoral regulation was assessed by spectral analysis of HR and BP, plasma catecholamine and aldosterone levels and plasma renin activity. Postprandial mesenteric hyperemia was associated with an increase in CO, a decrease in SVR and cardiac vagal tone, and reduction in baroreflex sensitivity with no change in sympathetic tone. Arterial α1-adrenoceptor responsiveness was preserved and reduced in hepatic sinusoids. Postprandial orthostasis was associated with a shift of 500 mL of blood from mesenteric to systemic circulation with preserved sympathetic-mediated vasoconstriction. Meal ingestion provokes cardiovascular hyperdynamism, cardiac vagolysis, and resetting of the baroreflex without activation of the sympathetic nervous system. Meal ingestion also alters α1-adrenoceptor responsiveness in the hepatic sinusoids and participates in the redistribution of blood volume from the mesenteric to the systemic circulation to maintain a normal BP during orthostasis.NEW & NOTEWORTHY A unique integrated investigation on the effect of meal on neurohumoral mechanisms and blood flow redistribution of the mesenteric circulation during orthostasis was investigated. Food ingestion results in cardiovascular hyperdynamism, reduction in cardiac vagal tone, and baroreflex sensitivity and causes a decrease in α1-adrenoceptor responsiveness only in the venous intrahepatic sinusoids. About 500-mL blood shifts from the mesenteric to the systemic circulation during orthostasis. Accordingly, the orthostatic homeostatic mechanisms are better understood.

The importance of serum intestinal fatty acid-binding protein for the early diagnosis of acute mesenteric ischemia.

BACKGROUND: Acute mesenteric ischemia (AMI), although relatively rare, is an emergency condition with high mortality rates (60-80%) attributed to lack of early diagnosis. The aim of this experimental study was to observe the changes in serum intestinal fatty acid-binding protein (I-FABP) levels over time in the AMI model by ligating superior mesenteric artery (SMA) in rats and to compare with the serum I-FABP levels of the rats in the control group. METHODS: Twenty rats were randomly allocated into two groups as control and ischemia group. The basal serum I-FABP levels were determined. SMA was isolated by laparotomy in all animals. In the ischemia group, SMA was ligated and intestinal ischemia was formed. Blood was taken from each rat in both groups at 30th, 60th, and 90th min to determine the serum I-FABP levels. The blood results were compared between two groups and were also compared by time in each group. RESULTS: In the ischemia group, serum I-FABP levels were significantly higher than the control group at post-operative 30th, 60th, and 90th min (p<0.01). In comparison with pre-operative serum I-FABP levels, remarkable increases were observed statistically at post-operative 30th, 60th, and 90th min in the ischemia group (p<0.01). In contrast, there was no statistically significant difference within the serum I-FABP levels over time in the control group. The increases of serum I-FABP levels in the ischemia group were directly correlated with the time of ischemia. CONCLUSION: Serum I-FABP levels have increased significantly in the intestinal ischemia and these values have risen progressively over time. Serum I-FABP may be a useful and promising biomarker for the early diagnosis of AMI.

Transcollateral Recanalization of an Occluded Superior Mesenteric Artery.

OBJECTIVE: To report the technique of transcollateral retrograde recanalization of a superior mesenteric artery flush occlusion. METHODS: The technique of a patient undergoing transcollateral retrograde recanalization for acute symptomatic superior mesenteric artery flush occlusion was reviewed and presented. Other adjunctive methods to facilitate the endovascular treatment of the superior mesenteric artery total occlusion lesion were also compared and discussed. RESULTS: The patient was a 47-year-old woman, acute onset of symptomatic chronic mesenteric ischemia with flush occlusion of the superior mesenteric artery which was unable to be revascularized in a routine operation. A collateral was found to connect celiac artery and superior mesenteric artery (gastroduodenal arch). The guidewire was retrograde crossed the occluded lesion via this collateral and recaptured by the catheter from the same single brachial sheath followed by balloon angioplasty and stent implantation. The patient recovered well and the symptoms completely disappeared after the procedure. CONCLUSION: The technique of retrograde recanalization through collateral pathway is an applicable alternative option for patients with superior mesenteric artery flush occlusion who have failed attempts by conventional antegrade approaches.

Use of Indocyanine Green During Repair of a Superior Mesenteric Artery Aneurysm.

Superior mesenteric artery (SMA) aneurysms are rare and associated with a high risk of rupture, with resultant significant morbidity and mortality. During open operative repair of a superior mesenteric artery aneurysm, perfusion of the involved small bowel must be evaluated when determining need for and/or extent of vascular reconstruction. We present a case of a 51-year-old woman who underwent open repair of a non-ruptured superior mesenteric artery aneurysm with ligation and excision, in whom no revascularization was determined to be needed and the involved small bowel was able to be preserved, with intraoperative evaluation of perfusion using indocyanine green (ICG) fluorescence imaging, as an adjunct to more traditional methods of perfusion assessment.

Midterm results after covered stenting of the superior mesenteric artery.

OBJECTIVE: Despite the continuing controversy of covered stents (CS) vs bare metal stents, the use of CS in mesenteric occlusive disease (MOD) has been recommended by expert centers. The aim of this study was to report midterm results with CS of the superior mesenteric artery. METHODS: Between January 2014 and October 2019, patients with MOD with a severe atheromatous stenosis or occlusion of the superior mesenteric artery treated by mesenteric CS were included. Clinical presentation included both acute mesenteric ischemia (AMI), chronic mesenteric ischemia, and asymptomatic patients planned for major surgery. Demographics, procedure details, and follow-up data were prospectively collected and retrospectively reviewed. Study end points included primary patency, primary assisted patency, and secondary patency. RESULTS: During the study period, 86 patients (mean age, 70 ± 9 years; 57% males) were included. Clinical presentation was AMI (n = 42 [49%]), chronic mesenteric ischemia (n = 31 [36%]), and asymptomatic (n = 13 [15%]). The technical success rate was 97%. A total of 96 stents were implanted, including 86 proximal CS (Advanta V12, n = 73; Lifestream, n = 13). The mean length and mean diameter of the CS were 31.5 ± 6.3 mm and 6.9 ± 0.5 mm, respectively. Additional distal bare metal stents were used in 10 patients (12%) to overcome a kinking (n = 9) or a dissection (n = 1) downstream of the CS. All postoperative deaths occurred in patients with AMI (n = 11, 13%). During a median follow-up of 15.6 months (95% confidence interval [CI], 15.6 ± 3.6 months), 12 patients (14%) underwent reinterventions for either stent misplacement (n = 3), stent recoil (n = 3), stent thrombosis (n = 2), de novo stenosis at the distal edge of the CS (n = 2), or gastric ischemia (n = 1). At 1 year, overall the primary patency, primary assisted patency, and secondary patency rates were 83% (95% CI, 83% ± 9%), 99% (95% CI, 99% ± 3%), and 99% (95% CI, 99% ± 3%), respectively. At 2 years, the overall primary patency, primary assisted patency, and secondary patency rates were 76% (95% CI, 76% ± 13%), 95% (95% CI, 95% ± 8%) and 95% (95% CI, 95% ± 8%), respectively. CONCLUSIONS: Mesenteric CS provide very satisfactory midterm results in patients with MOD, with an excellent primary assisted patency rate at 2 years, at the price of a significant reintervention rate.

Splanchnic occlusive disease predicts for spinal cord injury after open descending thoracic and thoracoabdominal aneurysm repair.

OBJECTIVE: In the present study, we sought to discern the effects of splanchnic occlusive disease (SOD; renal, superior mesenteric, and/or celiac axis arteries) on spinal cord injury (SCI; paraparesis or paraplegia) and major adverse events (MAE) after descending thoracic aneurysm (DTA) and thoracoabdominal aortic aneurysm (TAAA) open repair. METHODS: Patients who had undergone DTA/TAAA repair at our institution were dichotomized according to the presence of SOD, which was investigated as a predictive factor of our primary (SCI) and secondary (operative mortality, myocardial infarction, stroke, tracheostomy, de novo dialysis, MAE, survival) endpoints. Risk adjustment used both propensity score matching and multivariable logistic regression. RESULTS: From July 1997 to October 2019, 888 patients had undergone DTA/TAAA repair, of whom 19 were excluded from our analysis for missing data. SOD was absent in 712 patients and present in 157 patients. The patients with SOD had presented with a greater incidence of preoperative renal impairment (61 [38.9%] vs 175 [24.6%]; P < .01) and peripheral arterial disease (60 [38.2%] vs 162 [22.8%]; P < .01] and decreased left ventricular ejection fraction (45%; interquartile range, 10%; vs 50%; interquartile range, 4%; P < .01). The etiology of aortic disease was more frequently dissection in the SOD group (56.1% vs 43.7%) and more frequently nondissecting aneurysm in the non-SOD group (56.3% vs 43.9%; P < .01). Patients without SOD had presented with aneurysms more cranially located (DTA, 34.0% vs 7.6%; extent I TAAA, 44.0% vs 7.6%). In contrast, patients with SOD had presented with aneurysms more caudally located (extent II TAAA, 36.9% vs 8.6%; extent III TAAA, 30.6% vs 11.0%; extent IV TAAA, 17.2% vs 2.5%; P < .01). Propensity score matching led to 144 pairs, with SOD significantly associated with SCI (10 [6.9%] vs 2 [1.4%]; P = .03) and MAE (47 [32.6%] vs 26 [15%]; P < .01). Ten-year survival was reduced in those with SOD (31.5% vs 45.2%; P < .01). Conditional multivariable regression confirmed SOD to be a predictor of SCI in the matched sample (odds ratio, 6.60; P = .02). CONCLUSIONS: Our results have shown that SOD is a significant predictor of SCI in patients undergoing open DTA/TAAA repair. The investigation of measures to prolong neuronal ischemia tolerance (eg, hypothermia) is warranted for such patients.

Morphologic characteristics and endovascular management of acute type B dissection patients with superior mesenteric artery involvement.

OBJECTIVE: Despite its association with static mesenteric malperfusion, the morphologic characteristics and optimal management of acute type B aortic dissection (ABAD) with superior mesenteric artery (SMA) involvement are poorly understood. We studied the associated risk factors and reported the outcomes of endovascular treatment. METHODS: From May 2016 to May 2018, we examined 212 consecutive patients with ABAD in our center. Those with SMA involvement (SMAI) were included in the present study and divided into those with and without mesenteric malperfusion (MMP) according to the clinical findings. After thoracic endovascular aortic repair (TEVAR) with or without SMA revascularization, we compared the clinical data, imaging results, and outcomes for those with and without MMP. RESULTS: Computed tomography angiography confirmed 44 cases of SMAI: 12 (27.3%) with MMP and 32 (72.7%) without MMP. The patients with MMP had presented more frequently with lower extremity malperfusion (33.3% vs 3.1%; P = .023) than had those without MMP, with an odds ratio of 14.15 (P = .047). Multivariate analysis showed that patients with a low true lumen (TL)/false lumen (FL) diameter ratio of the SMA (TL/FL-SMA <1) had a greater risk of developing MMP than those with a high TL/FL-SMA ratio of >1 (odds ratio, 8.49; 95% confidence interval, 1.24-58.26; P = .029). SMA TL thrombosis was a significant predictor of the requirement for additional SMA revascularization after TEVAR among patients with MMP (P = .045). During a mean 10-month follow-up period, complete FL thrombosis in the SMA was seen in 11 patients (25%; 33.3% with MMP vs 21.9% without MMP; P = .43). The overall mortality rate was 6.82% (16.7% in the MMP group and 3.1% in the non-MMP group; P = .09). CONCLUSIONS: In the present study, limb ischemia and the TL/FL-SMA ratio were two independent predictors for the development of MMP in patients with ABAD and SMAI. We found that TEVAR can be safely performed for these patients, and SMA TL thrombosis predicted for the need for SMA revascularization.

Parallel Grafting Should Be Considered as a Viable Alternative to Open Repair in High-Risk Patients With Paravisceral Aortic Aneurysms.

BACKGROUND: Parallel grafting presents a viable method for treating patients with complex aortic aneurysms. The current literature is limited to mostly pararenal configurations. We examined our results in patients with SMA and/or Celiac artery involvement. METHODS: A retrospective analysis was performed for all patients undergoing parallel grafting during the period of 2014 to 2018 at a single institution. All patients had at least SMA with and/or without Celiac artery parallel grafting. RESULTS: Seventy-nine patients (65% male, median age 74) were treated with 208 parallel grafts. Median ASA score is 4. Forty-nine cases were elective, 22 urgent, and 8 emergent. Mean pre-operative aneurysm diameter was 7.1 cm (4.6-15 cm). Self-expanding covered stents were used for the renal arteries (mean 6.3mm), and balloon-expandable covered stents were used for the SMA and Celiac (mean SMA 8.6 mm, mean celiac 8.3 mm). Axillary exposure was the choice of access in 68 patients (86%). Technical success was achieved in all cases. We defined this as aneurysm sac exclusion with patent visceral stent grafts, and absent to mild gutter leaks. Mean aortic graft proximal seal achieved was 48mm. Coverage extended above the celiac artery in 75% (10% stented and 65% covered). Median contrast volume was 145ml, operative duration was 4 hours, fluoroscopy time was 56 min, and EBL was 250 ml. Perioperative mortality was 6.1%. 4.5%, and 25%, for the elective, urgent, and emergent groups, respectively. There was no incidence of spinal cord ischemia. Axillary access was complicated in 4 patients, requiring patch closure of the axillary artery. One patient developed postprocedural ESRD from a rupture and ATN despite patent renal stents. Of those patients with a patent GDA and celiac coverage, 2 required a cholecystectomy. Nine patients had a persistent gutter leak at the conclusion of the procedure. Median follow-up was 12 months. On follow-up imaging, all SMA and Celiac stents were patent. Six renal stents were occluded and 2 patients progressed to ESRD, both solitary renal periscope configurations at the index procedure. Only 4 patients had persistent gutter leaks with 2 requiring reintervention. Ninety-five percent of patients demonstrated sac regression or stabilization with a mean sac size of 6.5 cm. CONCLUSIONS: Parallel grafting presents a safe, efficacious and off the shelf alternative to conventional repair of complex aortic aneurysms involving the visceral aorta.

Sorafenib not only impairs endothelium-dependent relaxation but also promotes vasoconstriction through the upregulation of vasoconstrictive endothelin type B receptors.

As a VEGF-targeting agent, sorafenib has been used to treat a number of solid tumors but can easily lead to adverse vascular effects. To elucidate the underlying mechanism, rat mesenteric arteries were subjected to organ cultured in the presence of different concentrations of sorafenib (0, 3, 6 and 9 mg/L) with or without inhibitors (U0126, 10-5 M; SB203580, 10-5 M; SP200126, 10-5 M) of MAPK kinases, and then acetylcholine- or sodium nitroprusside-induced vasodilation and sarafotoxin 6c-induced vasoconstriction were monitored by a sensitive myograph. The NO synthetases, the nitrite levels, the endothelial marker CD31,the ETB and ETA receptors and the phosphorylation of MAPK kinases were studied. Next, rats were orally administrated by sorafenib for 4 weeks (7.5 and 15 mg/kg/day), and their blood pressure, plasma ET-1, the ETB and ETA receptors and the phosphorylation of MAPK kinases in the mesenteric arteries were investigated. The results showed that sorafenib impairs endothelium-dependent vasodilation due to decreased NO levels and the low expression of eNOS and iNOS. Weak staining for CD31 indicated that sorafenib induced endothelial damage. Moreover, sorafenib caused the upregulation of vasoconstrictive ETB receptors, the enhancement of ETB receptor-mediated vasoconstriction and the activation of JNK/MAPK. Blocking the JNK, ERK1/2 and p38/MAPK signaling pathways by using the inhibitors significantly abolished ETB receptor-mediated vasoconstriction. Furthermore, it was observed that the oral administration of sorafenib caused an increase in blood pressure and plasma ET-1, upregulation of the ETB receptor and the activation of JNK in the mesenteric arteries. In conclusion, sorafenib not only impairs endothelium-dependent vasodilatation but also enhances ETB receptor-mediated vasoconstriction, which may be the causal factors for hypertension and other adverse vascular effects in patients treated with sorafenib.

Defining Duplex Ultrasound Criteria for In-Stent Restenosis of the Superior Mesenteric Artery.

BACKGROUND: This study sought to define duplex ultrasound (DUS) velocity criteria predicting ≥70% stenosis in superior mesenteric artery (SMA) stents by correlating in-stent peak systolic velocity (PSV) with computed tomographic angiography (CTA) measurements of percent stenosis. METHODS: A retrospective review of 109 patients undergoing SMA stenting between 2003 and 2018 was conducted at a single institution. Thirty-seven surveillance duplex ultrasound studies were found to have a CTA performed within 30 days of study completion. Bare metal (n = 20) and covered stents (n = 17) were included. Velocities were paired to in-stent restenosis (ISR) measured by mean vessel diameter reduction on SMA centerline reconstructions from CTA. Receiver operating characteristic (ROC) curves was generated and logistic regression models for ≥70% ISR probability were used to define velocity criteria in the stented SMA. RESULTS: At a PSV of 300 cm/sec, the sensitivity is 100% and specificity 80% for a ≥70% in-stent SMA stenosis. At a PSV of 400 cm/sec, the sensitivity and positive predictive value (PPV) is 63% and the specificity and negative predictive value (NPV) is 90%. A PSV of 450 cm/sec was consistent with the highest specificity (100%) and PPV (100%) but lower sensitivity (50%) and NPV (87.9%). One patient with a PSV of 441 cm/sec on surveillance DUS died from complications of acute-on-chronic mesenteric ischemia. CONCLUSIONS: A PSV of 400 cm/sec on mesenteric DUS can predict ≥70% ISR with high sensitivity and should be considered as a diagnostic threshold for SMA in-stent restenosis.

Effects of preoperative visceral artery stenosis on target artery outcomes after fenestrated/branched endovascular aortic aneurysm repair.

OBJECTIVE: Target artery stenosis might affect the outcomes of fenestrated/branched endovascular aortic aneurysm repair (F-BEVAR). The aim of the present study was to assess the effects of preoperative stenosis of the celiac artery (CA) and superior mesenteric artery (SMA) on the target artery outcomes after F-BEVAR. METHODS: During a 4-year period, 287 consecutive patients, 204 men (71%) and 83 women (29%), had undergone F-BEVAR using fenestrated (83%), fenestrated-branched (4.5%), branched (3.5%), and off-the-shelf t-Branch (9%) devices (Cook Medical Inc, Bloomington, Ind). Preoperative SMA and CA significant stenosis was defined as a computed tomography angiography-based intraluminal diameter reduction >50%. The primary endpoints included primary patency, freedom from target vessel instability, and patient survival. RESULTS: The median patient age was 71 years (interquartile range, 67-77 years). Suprarenal (36%), juxtarenal (25%), and thoracoabdominal (39%) aortic aneurysms were treated. The technical success rate was 99%. The 30-day survival was 97%. Among 981 stented vessels, 179 (18%) were CAs and 270 (27.5%) were SMAs. Significant preoperative CA stenosis was identified in 39 patients (22%) and SMA stenosis in 24 (9%). The median follow-up was 29.9 months. The primary patency rates at 12, 36, and 60 months were 98%, 92%, and 92% for the CA and 99%, 98%, and 98% for the SMA, respectively. Primary patency was significantly lower in the patients with previous significant CA stenosis than in those without stenosis (83%, 83%, and 76% vs 100%, 100%, and 97% at 12, 36, and 60 months, respectively; P < .01). Freedom from celiac branch instability was also significantly lower among patients with significant stenosis (84%, 84%, and 76% vs 100%, 93%, and 93% at 12, 36, and 60 months; P < .01). The presence of significant SMA stenosis did not affect either primary patency or freedom from target vessel instability. The survival rates at 12, 36, and 60 months were significantly lower for the patients with CA stenosis than for those without stenosis (67%, 61%, and 55% vs 90%, 84%, and 82%, respectively; P < .01). Similarly, lower survival rates were observed for patients with significant SMA stenosis (70%, 60%, and 60% vs 87%, 79%, and 78% at 12, 36, and 60 months, respectively; P = .04). CONCLUSIONS: F-BEVAR was associated with overall primary patency rates >90% for the CA and SMA. Preoperative CA stenosis was associated with lower primary patency and freedom from target vessel instability. In contrast, neither SMA branch primary patency nor freedom from target vessel instability were affected by preoperative SMA stenosis. We found visceral artery stenosis was a marker of atherosclerosis burden associated with reduced mid- and long-term patient survival.

The impact of endovascular treatment on clinical outcomes of stable symptomatic patients with spontaneous superior mesenteric artery dissection.

OBJECTIVE: To evaluate the efficacy and clinical outcomes of endovascular treatment for superior mesenteric artery dissection (SMAD) and its effect on superior mesenteric artery (SMA) remodeling compared with medical management alone after successful initial medical management. METHODS: In this retrospective analysis, all patients with spontaneous SMAD at a single institution were identified from March 2007 to August 2019. The primary outcomes were freedom from major adverse events (MAEs, a composite of dissection-related death, the recurrence of mesenteric ischemia symptoms, and a requirement for intervention). The secondary outcomes were morphologic remodeling of the dissections and stenosis or occlusion of the SMA. RESULTS: A total of 94 patients with SMAD who underwent successful initial medical management (91 males; mean age, 50.4 ± 6.3 years) were enrolled in the study. Fifty-seven (60.6%) received medical management alone, and 37 (39.4%) underwent endovascular repair after initial medical management. In the endovascular group, the technical success rate was 86.5% (32 of 37). During a mean follow-up period of 33.6 ± 26.2 months (range, 1-120 months), nine (9.6%) patients experienced a recurrence of abdominal pain, and six had additional interventions for SMAD. The patients in the endovascular group showed more complete or partial remodeling (22 [81.1%] vs 24 [44.4%]; P < .0001) or unchanged dissections (5 [13.5%] vs 23 [42.6%]; P = .0001) than those in the conservative group. Survival analysis showed that the estimated MAE-free survival rates were 95.6%, 88.9%, and 85.4% at 1, 3, and 5 years, respectively. There was a higher freedom from SMA stenosis or occlusion in the endovascular group (log rank P = .046). CONCLUSIONS: Endovascular treatment and medical management alone result in similar MAE-free survival for patients with SMAD after successful initial medical management. Moreover, endovascular therapy is associated with a higher complete remodeling rate and greater freedom from SMA stenosis or occlusion.

Experience of managing superior mesenteric artery aneurysm and its midterm follow-up results with 18 cases.

OBJECTIVES: To characterize the clinical features, treatment, and prognosis of superior mesenteric artery aneurysms and provide evidence for clinical decision-making. METHODS: We retrospectively reviewed the diagnosis and treatment of 18 cases of superior mesenteric artery aneurysm admitted to our center from 2003 to 2020, including demographic data, risk factors, clinical manifestations, diagnosis, treatment strategies, and follow-up results. RESULTS: The average age of the patients was 49.1 years, and males accounted 83.3%. The development of the disease was associated with infection, hypertension, pancreatitis, and trauma, but no significant associations with atherosclerosis were noted by our results. Nine patients were diagnosed with true aneurysm, seven patients with pseudoaneurysm, and two patients with dissecting aneurysm. Rupture of aneurysm occurred in three patients (16.7%), and one of them died before surgery. The surgery success rate was 94.1%, and open surgery was performed on nine patients, endovascular surgery on three patients, and conservative treatment on three patients. The follow-up rate was 77.8% (14/18), and the average follow-up time was 48.2 months. The mortality and reintervention rate during follow-up was 0. The two-year patency rate of artificial vessels and covered stents was 50%. CONCLUSION: The clinical manifestations and features of superior mesenteric artery aneurysms vary between patients. Careful evaluation of vascular anatomy and personalized treatment strategy are critical in the management of superior mesenteric artery aneurysms. Midterm follow-up results of superior mesenteric artery aneurysms are satisfactory.

"Flaring-Kissing Ballooning" of the Stentgrafts in Fenestrated Endograft Procedures to Ensure Target Visceral Vessels Patency.

PURPOSE: To describe a dedicated technique used in fenestrated endografting (FEVAR) for juxtarenal aneurysm (JAAA) to avoid intraoperative bridging stentgraft crushing in case of adjacent origin of left renal (LRA) and superior mesenteric (SMA) artery. CASE REPORT: A 78-year-old male, at high surgical risk, underwent FEVAR for JAAA. SMA and LRA fenestrations were adjacent, at 12:30 and 2:45 o'clock evaluation, respectively. The fenestrated endograft and the bridging stentgrafts for target visceral vessels (TVVs) were deployed without complications. The completion angiography and the cone-beam CT showed patency of TVVs, except for LRA, which showed crushing of its stentgraft. SMA and LRA were re-cannulated, and the renal stentgraft was dilated with a 4 × 40 mm balloon. Finally, "Flaring-Kissing ballooning" of SMA and LRA stentgrafts was performed using two 10 × 20 mm balloon under fluoroscopy rotational guidance, to ensure the patency of both arteries. The completion angiography and the postoperative CT-angiography showed the resolution of the crushing and the patency of TVVs. The postoperative course was uneventful; the patient was discharged home after 5 days. CT-angiography at 12 months showed patency of TVVs and no endoleaks. CONCLUSIONS: The "Flaring-Kissing ballooning" of adjacent stentgrafts is a valid, safe and effective intra-procedural maneuver to preserve the patency of the TVVs.

Peritoneal dialysis-related peritonitis complicated with nonocclusive mesenteric ischemia.

Peritoneal dialysis (PD)-related peritonitis is a common complication of PD. Nonocclusive mesenteric ischemia (NOMI) is a rare complication of PD-related peritonitis, has a high mortality rate, and therefore should be detected early once it occurs. We describe a case of a 70-year-old woman on PD presented with moderate abdominal pain and low blood pressure, which contributed to the early diagnosis of PD-related peritonitis complicated with NOMI. Increased white cell count of 7150/µL (neutrophil, 84%) in dialysate effluent was diagnostic of PD-related peritonitis, which was later found to be caused by Pseudomonas putida. Computed tomography with contrast performed after administering crystalloids revealed hepatic portal venous gas, pneumatosis intestinalis in the ascending colon, and normal enhancement of the bowel wall and mesenteric arteries, which suggested a reperfusion of the previously ischemic ascending colon. Colonoscopy on hospital day seventeen revealed mucosal hemorrhage and ulcers in the entire right colon and the terminal ileum while the remaining colon was normal. These findings are compatible with the consequence of NOMI. Increased peak systolic velocity of the superior mesenteric artery (SMA) implied its stenosis. Past studies show that ischemia of the colon in patients with chronic kidney disease commonly occurs in the right colon. Arteriosclerosis of the SMA due to the long history of chronic kidney disease and diabetes might have caused its vulnerability to low blood pressure. Abdominal complications including NOMI should be screened for when a patient presents with low blood pressure and strong abdominal pain. This is the first case report that shows colonoscopy images of the colonic ulcers post-NOMI and PD-related peritonitis.